Radon is one of those invisible risks that can easily be overlooked during the excitement of buying or selling a home. It’s a naturally occurring radioactive gas that comes from the ground and can accumulate inside any structure, regardless of age or location. Because radon has no smell, color, or taste, testing is the only way to detect it. The Environmental Protection Agency (EPA) highly advises conducting radon tests during every real estate deal to guarantee that both buyers and sellers are informed about safety and property worth.

Timing is everything when it comes to radon testing during a home sale. Knowing when—and how—to test can prevent unexpected delays and protect everyone involved in the deal.

The Best Time to Test: During the Inspection Window

The most practical time to test for radon is during the home inspection period. This is usually the window of time between an accepted offer and closing, when buyers complete due diligence. Because radon tests typically take several days, it’s important to schedule the test early in this process. Most inspectors can perform a radon test as part of the general home inspection, but it must be requested specifically—it isn’t automatically included.

Testing during the inspection period ensures results are available before closing, giving both parties time to address elevated levels if needed. If radon levels come back above the EPA’s action level of 4.0 pCi/L, the buyer and seller can negotiate mitigation before the deal is finalized.

For Sellers: Why Early Testing Pays Off

Sellers who test for radon before listing their property often save time and stress later. By identifying any radon issues early, you can have them resolved before a buyer even steps in. This proactive approach signals transparency and responsibility—qualities that make buyers more confident in your home.

In most states, any known radon test results must be disclosed to potential buyers. Having documentation of a recent test showing safe levels can be a selling advantage. Even if mitigation was needed, showing that it’s been completed by a professional gives your property a clean bill of health and reduces negotiation hurdles later on.

For Buyers: Don’t Skip the Test

Even if a seller has already performed a radon test, buyers should still request their own test during the home inspection period. Radon levels can fluctuate seasonally and may vary depending on changes in the home’s structure, ventilation, or foundation. A fresh test ensures you’re getting accurate information based on current conditions.

If radon levels are high, the issue can typically be resolved before closing. Buyers can request that the seller install a mitigation system or provide a credit toward one. Since mitigation systems are effective and affordable, elevated radon should not deter you from purchasing the home—it’s simply an issue to be addressed like any other maintenance concern.

Testing Vacant Homes: What to Know

It’s perfectly acceptable to test vacant homes for radon, as long as the property has been closed up for at least 12 hours before starting the test. This allows the indoor air to stabilize to normal living conditions. Maintain closed windows and doors, apart from regular entry and exit, and make sure the heating or cooling system is functioning properly throughout the test.

Short-term tests, which take between 48 hours and 7 days, are commonly used in real estate deals because they deliver fast results. The key is maintaining “closed-house conditions” throughout the test to get an accurate reading.

What Happens If High Radon Levels Are Found?

If the test result is 4.0 pCi/L or higher, the EPA recommends mitigation. Fortunately, high radon levels are not cause for panic. Professional mitigation systems can typically be installed in one day and work by venting radon gas safely outside. Once the system is in place, a follow-up test confirms that the radon level has dropped to a safe range—usually between 1.0 and 3.0 pCi/L.

In most cases, mitigation becomes part of the negotiation process, just like other home repairs. The cost is modest compared to the overall value of a home and the health protection it provides.

Radon Testing and Real Estate: Key Takeaways

• Radon testing should occur during the home inspection period.
• Sellers benefit from testing early to avoid surprises later.
• Buyers should always confirm test results, even if the home was previously tested.
• Vacant homes can be tested accurately with proper preparation.
• Radon issues are easily fixed—elevated levels shouldn’t derail a sale.

Learn More

For more detailed information about radon testing in real estate transactions, visit the EPA’s official guide:
Home Buyer’s and Seller’s Guide to Radon.

About Radon Delete

Radon Delete helps homeowners, buyers, and real estate professionals navigate radon testing and mitigation with confidence. Their certified technicians specialize in fast, accurate testing and efficient mitigation systems tailored for home sales. Whether you’re preparing to list a property or finalizing a purchase, Radon Delete ensures your transaction meets safety standards and gives everyone peace of mind before closing.